Re: [RESEND][PATCH v15 2/4] perf: Support deferred user callchains

On Mon, Sep 08, 2025 at 01:14:14PM -0400, Steven Rostedt wrote:

+	/*
+	 * All accesses related to the event are within the same RCU section in
+	 * perf_event_callchain_deferred(). The RCU grace period before the
+	 * event is freed will make sure all those accesses are complete by then.
+	 */
+	rcuwait_wait_event(&event->pending_unwind_wait, !event->pending_unwind_callback, TASK_UNINTERRUPTIBLE);

You need a narrower terminal, this is again excessive. I mostly code
with my screen split in 4 columns (3 if I can't find my glasses), and
that gets me around 90 character columns.

+	if (event->attr.defer_callchain)
+		init_task_work(&event->pending_unwind_work,
+			       perf_event_callchain_deferred);

And let me hand you a bucket of {}, I've heard they're getting expensive
over in the US due to this tariff nonsense :-)